1.
If food, wood, or another substance is rotten, it has decayed and can no longer be used.
The smell outside this building is overwhelming-like rotten eggs...
ADJ
2.
If you describe something as rotten, you think it is very unpleasant or of very poor quality. (INFORMAL)
I personally think it's a rotten idea...
? great
ADJ: usu ADJ n
3.
If you describe someone as rotten, you are insulting them or criticizing them because you think that they are very unpleasant or unkind. (INFORMAL)
You rotten swine! How dare you?...
? nice
ADJ: usu ADJ n [disapproval]
4.
If you feel rotten, you feel bad, either because you are ill or because you are sorry about something. (INFORMAL)
I had glandular fever and spent that year feeling rotten...
= awful
ADJ: usu v-link ADJ